Nothing can sharpen your programming skill and motivate you to learn quite like having a project to engage in. Also having more experienced coders giving you feedback can be invaluable. As such (and keep in mind, I have absolutely no say over who is involved in this project), involving yourself in a project like this could be helpful.

Having said all that, you'll need to up your game beforehand. There's a set of things you'll have to learn about C++ and programming in general that's best learned by reading, writing out your own programs and maybe asking others if you're stuck. When I was learning, I tried out Sams Teach Yourself C++ in 21 Days and made and ran some programs in Dev-Cpp. That's kinda a bit outdated, but the essential thing is to find some tutorials and/or C++ learning resources (I've heard some good things about Bruce Eckel's free ebook Thinking in C++) and get an IDE to program in (I'm not the keenest on the open source Code::Blocks, but it should get you off the ground). Start with basic programs, learn more about C++ as you make more advanced programs and try new things, maybe even forcus a lot of energy on an area that interests you. I don't know whether you'd be able to join the Mobius Project when you've got to that stage (not my decision), but it would put you in a heck of a lot better position.

PS. I apologise if you've actually got more programming knowledge and some of what I said sounds obvious to you, but your post implies you're a newbie to this, so I took that as the case.

Yeah, reading books and theory is fine and great, but programming is a skill, and skills are developed through a bit of theory, and a lot of doing the actual thing.

If you want any help, feel free to chat with me on AIM, in the meantime, I'd suggest making a very basic game in SDL to get comfortable (what sort of game depends on you, but keep it simple to start with). These are some good SDL tutorials.